U.S. patent number 4,778,832 [Application Number 07/060,523] was granted by the patent office on 1988-10-18 for dental precise impression materials comprising silicone.
This patent grant is currently assigned to G-C Dental Industrial Corp.. Invention is credited to Shunichi Futami, Satoshi Terauchi.
United States Patent |
4,778,832 |
Futami , et al. |
October 18, 1988 |
Dental precise impression materials comprising silicone
Abstract
A dental precise impression material comprises condensation or
addition type room temperature-vulcanizing silicone, and further
contains 0.1 to 10.0 weight % of at least one protein soluble or
slightly soluble in water optionally with 0.05 to 5.0 weight % of
at least one hydrophilic nature-affording agent selected from
hydrophilic silicone oils and nonionic surface active agents.
Inventors: |
Futami; Shunichi (Nagareyama,
JP), Terauchi; Satoshi (Gotenba, JP) |
Assignee: |
G-C Dental Industrial Corp.
(Tokyo, JP)
|
Family
ID: |
15658755 |
Appl.
No.: |
07/060,523 |
Filed: |
June 11, 1987 |
Foreign Application Priority Data
|
|
|
|
|
Jul 7, 1986 [JP] |
|
|
61-157851 |
|
Current U.S.
Class: |
523/109; 106/35;
524/17 |
Current CPC
Class: |
A61K
6/90 (20200101) |
Current International
Class: |
A61K
6/10 (20060101); A61K 006/10 () |
Field of
Search: |
;106/35 ;523/109
;524/17 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Morris; Theodore
Attorney, Agent or Firm: Oblon, Fisher, Spivak, McClelland
& Maier
Claims
What is claimed is:
1. A dental precise impression material comprising condensation or
addition type room temperature-vulcanizing silicone, which further
contains 0.1 to 10.0 weight % of at least one protein soluble or
slightly soluble in water.
2. A dental precise impression material comprising condensation or
addition type room temperature-vulcanizing silicone, which further
contains 0.1 to 10.0 weight % of at least one protein soluble or
slightly soluble in water, and 0.05 to 5.0 weight % of at least one
hydrophilic nature-affording agent selected from the hydrophilic
silicone oils and nonionic surface active agents.
3. The dental precise impression material of claim 1, wherein said
protein is one member selected from the group consisting of
albumin, globulin, gluten, histone, and protamine.
4. The dental precise impression material of claim 1, wherein said
protein is one member selected from the group consisting of casein,
vitellin, keratin, phosvitin, albumin tannate, and gelatin
tannate.
5. The dental precise impression material of claim 1, wherein said
protein is one member selected from the group consisting of
gelatin, proteose, and peptone.
6. The dental precise impression material of claim 2, wherein said
hydrophilic nature-affording agent is a hydrophilic silicone oil
selected from the group consisting of polyether-modified silicone
oil and alcohol-modified silicone oil.
7. The dental precise impression material of claim 2, wherein said
nonionic surface active agent is a polyether.
8. The dental precise impression material of claim 7, wherein said
polyether is one member selected from the group consisting of
polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl
ether, and polyoxyethylene alkyl phenyl ether.
9. The dental precise impression material of claim 2, wherein said
nonionic surface active agent is a partial ester of a polyhydric
alcohol with a fatty acid.
10. The dental precise impression material of claim 9, wherein said
polyhydric alcohol is one member selected from the group consisting
of sorbitan, glycerin, polyglycerin, ethylene glycol, polyethylene
glycol, propylene glycol and pentaerythritol.
11. The dental precise impression material of claim 2, wherein said
nonionic surface active agent is a mixed polyether ester of a
polyhydric alcohol.
12. The dental precise impresson material of claim 11, wherein said
mixed polyether ester is selected from the group consisting of
polyoxyethylene sorbitan fatty acid esters, polyoxyethylene
sorbitol fatty acid esters, polyoxyethylene mannitan fatty acid
esters, polyoxyethylene glyceryl fatty acid esters, and
polyoxyethylene propylene glycol mono-fatty acid esters.
13. The dental precise impression material of claim 2, wherein said
nonionic surface active agent is an ester of the addition product
of ethyleneoxide with one member of the group consisting of caster
oil, lanolin, phytosterol, and beeswax.
14. The dental precise impression material of claim 2, wherein said
nonionic surface active agent is one member selected from the group
consisting of Rf--O(C.sub.n H.sub.2n O).sub.n H, Rf(CH.sub.2).sub.l
O(C.sub.n H.sub.2n O).sub.m, and RfBn(R')(C.sub.2 H.sub.4 O).sub.n
H, wherein Rf is a fluorinated aliphatic or aromatic group having
1-20 carbon atoms, B is a divalant connecting group, R' is a
hydrogen atom or an alkyl group having 1-20 carbon atoms, and l, m,
and n each are an integer of 1-50.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a moulding material (hereinafter
referred to as the impression material) used for the preparation of
the oral tissue models required for the preparation of dental
prostheses such as crowns, inlays or dentures and, more especially,
to a dental precise impression material comprising silicone, which
is designed to be used for precise impression material.
2. Statement of the Prior Art
Dental impression materials are generally broken down into
non-elastic and elastic types.
The non-elastic impression materials may include those formed of
wax, gypsum, modelling compounds and the like. With the non-elastic
impression materials, however, it is hardly possible to achieve any
precise moulding (impression) of the teeth, arrangement of the
teeth, jaw and mucosa, each having a complicated shape and form and
including undercuts, of the oral cavity, since they undergo no
elastic deformation. Because of this, general moulding (impression)
of the oral cavity is presently carried out with modelling
compounds to form an individual tray, which is merely used in
combined impression with other precise impression materials.
The elastic impresstion materials may include those formed of agar,
alginates, polysulfide rubber, polyether rubber, silicone rubber
and the like. The elastic impression materials make it possible to
take the impressions of the teeth, arrangement of the teeth, jaw
and mucosa, each having a complicated shape and form and including
undercuts, of the oral cavity, since they are elastically
deformable so that, when removing the impression from within the
oral cavity, their deformation, if any, is restorable to the
original form.
While the agar or alginate impression materials are advantageous in
that they show a suitable degree of elasticity from the clinical
point-of-view, and are easy to handle and relatively inexpensive,
they are disadvantageous in that they undergo a considerable extent
of permanent deformation, and that the impression obtained
therefrom and taken out of the oral cavity changes largely in
dimensions with the lapse of time due to their large amount of
moisture content and tends to be readily torn due to their low tear
strength. For those reasons, they are mainly used for snap
impression.
The synthetic rubber-based impression materials obtained by using a
raw material e.g., polysulfide rubber, polyether rubber and
silicone rubber are used for precise impression, since they show a
suitable degree of elasticity from the clinical point-of-view, are
easy to handle and give rise to fairly small permanent deformation,
and provide cured products which show only limited dimensional
changes with the lapse of time and high tear strength.
Of the types of synthetic rubber forming the impression materials,
the polysulfide rubber is disdvantageous in that it gives out
strong offensive odor, and is cured too slowly; and the polyether
rubber is of reduced elasticity and hard, and is largely affected
by moisture. However, the silicone rubber is most frequency used as
the impression material, because it provides a material which is
tasteless and odorless, is sharply cured, excels in elasticity and
exhibits excellent dimensional stability owing to its extremely
limited dimensional change.
Depending upon the curing manner involved, the silicone rubber is
classified into the condensation type and the addition type. Such
room temperature-vulcanization silicone rubber is utilized as the
dental silicone impression material. In general, one of the
condensation type silicone impression material is available on one
hand in the form comprising a base component consisting of a
hydroxydimethyl polysiloxane having hydroxide groups at its both
terminals and a catalyst component consisting of an alkyl
orthosilicate and an organic tin compound which, in use, are mixed
and kneaded together by an operator (typically a dentist) to
prepare a mixture, which is then subjected to condensation
vulcanization and setting at normal temperature to provide elastic
silicone rubber, whereas the other is available in the form
comprising a base component consisting of a hydroxydimethyl
polysiloxane having hydroxide groups at its both terminals, a
crosslinker (reactor) component consisting of alkyl orthosilicate
and a catalyst component consisting of an organic tin compoubnd
which, in use, are mixed and kneaded together by an operator to
obtain a mixture, which is then subjected to condensation
vulcanization and setting at normal temperature to provide elastic
silicone rubber.
On the other hand, the addition type impression materials are
generally available in the form comprising a base component
consisting of a hydrogen polymethylsiloxane and a catalyst
component consisting of a vinyl polymethylsiloxane having a vinyl
group and a platinum catalyst added thereto, which, in use, are
mixed and kneaded together by an operator to obtain a mixture,
which is then subjected to addition vulcanization and setting at
normal temperature to provide elastic silicone rubber.
The silicone impression materials based on such silicone rubber
have the following excellent features:
1. They are readily mixable and kneadable.
2. They are sharply set in the oral cavity.
3. They excel in elastic recovery.
4. The surface of a gypsum model is smooth.
5. They provide a set body which undergoes only limited dimensional
changes and, hence, excels in dimensional stability.
6. They are tasteless and odorless.
Thus, the best use is now made of the silicone impression
materials.
With the silicone impression materials, however, it is difficult to
take the precise impressions of the details of the oral cavity and,
hence, reproduce precisely the details of the oral cavity on a
gypsum model, when the oral cavity is wetted with blood, saliva or
other fluids. This is because the silicone rubber possesses water
repellency as one of its properties.
More specifically, when the oral cavity is wetted with saliva
blood, or other fluids at the time of taking the impression of the
oral cavity, the blood, saliva or other fluids are forced into the
details such as interdentiums, margins of the teeth or pits and
fissures in the teeth by the silicone impression material, and are
allowed to remain there, since the silicone impression material
shows unsatisfactory compatibility with respect to blood, saliva or
other fluids. There is now a tendency that impression is carried
out in that state, which renders it difficult to take detailed and
precise impressions. At the time of impression, it is thus required
for an operator to blow air to the regions of the oral cavity, the
impressions of which are to be taken, followed by sufficient
drying. This operation is troublesome for not only an operator but
also a patient, and is especially difficult to apply to an infant
or bleeding regions. At the time of the preparation of a gypsum
model, there is a tendency that gypsum slurry is repelled on the
registered surface of the impression taken, thus rendering it hard
to cast it into the details of the registered surface and bringing
about easy entrainment of air bubbles therein, since that surface
shows unsatisfactory compatibility with respect to the gypsum
slurry. It is thus difficult to precisely transfer the details of
the registered surface onto the gypsum model. For that reason, it
is required for an operator to cast the gypsum slurry into the
details of the registered surface, while applying it thereonto in
small portions by means of a brush. This operation needs careful
attention, and is very troublesome for an operator. In order to
solve the above-mentioned problems arising from the unsatisfactory
wettability and compatibility which the silicone impression
material show with respect to saliva, blood or other fluids or
gypsum slurry, the addition of nonionic surface active agents to
the silicone impression materials has hitherto been considered.
However, large amounts of such nonionic surfactants have had to be
added to the silicone impression materials for the purpose of
eliminating the wettability and compatibility problems. As a
result, other problems arise, such as deteriorations of the
physical properties due to inhibited setting reaction of silicone
rubber and surface roughening of the gypsum model.
SUMMARY OF THE INVENTION
The present inventors have made intensive and extensive studies
with a view to providing a solution to the problems without
interferring with the setting reaction of silicone rubber, said
problems arising from the unsatisfactory compatibility the silicone
impression materials show with respect to blood, saliva or other
fluids present in the oral cavity because of the water repellency
of silicone rubber and the unsatisfactory compatibility the
registered surface of the impression taken exhibits with respect to
gypsum slurry. In consequence, it has unexpectedly been found that
such compatibility problems can effectively be solved by adding to
the silicone impression materials at least one protein soluble or
slightly soluble in water or a combination of said protein with at
least one hydrophilic nature-affording agent selected from
hydrophilic silicone oils and nonionic surface active agents.
According to one aspect of the present invention, there is provided
a dental precise impression material formed of condensation or
addition type room temperature-vulcanizing silicone, which is
characterized in that it further contains 0.1 to 10.0 weight % of
at least one protein soluble or slightly soluble in water.
According to another aspect of the present invention, there is
provided a dental precise impression material formed of
condensation or addition type room temperature-vulcanizing
silicone, which is characterized in that it further contains 0.1 to
10.0 weight % of at least one protein soluble or slightly soluble
in water, and 0.05 to 5.0 weight % of at least one hydrophilic
nature-affording agent selected from hydrophilic silicone oils and
nonionic surface active agents.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The protein soluble or slightly soluble in water shows satisfactory
affinity with respect to saliva, blood or other fluids.
Accordingly, if that protein is previously contained in the
silicone impression materials, then the property of silicone rubber
that repels blood, saliva or other fluids is reduced or limited so
that the unsatisfactory compatibility of the silicone impression
materials with respect thereto is improved. The protein soluble or
slightly soluble in water does not interfere with the addition or
condensation vulcanization of silicone rubber whatsoever and,
hence, may not possibly give rise to a lowering of the physical
properties of the silicone impression materials.
Therefore, the silicone impression materials containing the protein
soluble or slightly soluble in water still have the same
satisfactory features as those of the conventional silicone
impression materials. Since the impression materials according to
the present invention completely force the blood, saliva and other
fluids out of the details such as interdentiums, margins of the
teeth and pits and fissures in the teeth, they can be cast into
such details to achieve precise impression, even when the oral
cavity is wetted with blood, saliva and other fluids at the time of
impression. At the time of preparing a gypsum model, the materials
according to the present invention reduce or limit the repelling
action of silicone rubber upon gypsum slurry, so that the
wettability of the gypsum slurry with respect to the registered
surface of the impression is improved, and, in particular, the
gypsum slurry is cast into the details of the registered surface of
the impression without recourse to any operation for applying it on
that surface in small portions by means of a brush and with no
substantial fear of air bubble entrainment, whereby the details of
the registered surface of the impression can precisely be
transferred onto the gypsum model. When used in combination with
the protein soluble or slightly soluble in water, the hydrophilic
nature-affording agents, such as hydrophilic silicone oils and
nonionic surface active agents are effective, even in a small
amount, for complete elimination of the water repellancy of
silicone rubber. Especially where impression is carried out while
the oral cavity is wetted with water just after washing with water,
or the impression of a gypsum model wetted with water is taken to
obtain a duplicate impression on the basis of that gypsum model,
the wettability of silicone rubber with respect to the surface of
the oral cavity, the impression of which is to be taken, and the
surface of the gypsum model is much more improved, as compared with
sole addition of the protein soluble or slightly soluble in water
to the silicone impression materials.
The proteins usable for the present invention include simple,
conjugated and derived proteins soluble or slightly soluble in
water. Albumin, globulin, gluten, histone, protamine, etc. may be
mentioned for the simple proteins; casein, vitellin, keratin,
phosvitin, albumin tannate, gelatin tannate, etc. for the
conjugated proteins; and gelatin, proteose, peptone, etc. for the
derived proteins. Among them, preference is given to albumin,
protamine, gelatin, peptone, casein, albumin tannate and gelatin
tannate. These proteins soluble or slightly soluble in water may be
added alone or in combination to the silicone impression
materials.
Water-insoluble proteins do not lend themselves to the present
invention, since they have no affinity effect upon saliva and
blood. The amount of the proteins, soluble or slightly soluble in
water, added to the silicone impression materials should inevitably
be determined, taking into consideration their affinity effect upon
saliva and blood, their workability and elasticity and their
compatibility with respect to gypsum.
That is to say, when used in an amount of below 0.1 weight % with
the silicone impression materials, the protein soluble or slightly
soluble in water shows on the one hand no affinity effect upon
saliva and blood. On the other hand, the use of that protein in an
amount exceeding 10.0 weight % is unsuitable, because the elastic
properties, especially permanent deformation, of the silicone
impression materials deteriorate too largely to take precise
impressions, and the solidification reaction of gypsum is
inhibited, resulting in surface roughening of a gypsum model.
Therefore, it is preferred that the amount of the protein soluble
or slightly soluble in water to be contained in the silicone
impression materials is in the range of 0.1 to 10.0 weight %.
Mentioned below are the hydrophilic nature-affording agents, such
as hydrophilic silicone oils and nonionic surfactants, to be added
to the silicone impression materials in combination with the
protein soluble or slightly soluble in water. Suitable hydrophilic
silicone oils may include polyether-modified silicone oil and
alcohol-modified silicone oil. Suitable nonionic surface active
agents may include those having either an alkyl group, viz., a
lipophilic group, combined with a hydrophilic group, or a
hydrophilic group combined with a fluorocarbon group wherein the
hydrogen atoms in an alkyl group, viz., a lipophilic group are
substituted with fluorine. Ionic surface active agents are
unsuitable, since they inhibit the setting reaction of silicone
rubber, and roughen the surface of gypsum models. The nonionic
surface active agents usable in the present invention and having an
alkyl group, that is a lipophilic group, combined with a
hydrophilic group include:
(A) ether types wherein the number of addition moles of ethylene
oxide or propylene oxide is 1 to 30, and an alkyl group has 12 to
22 carbon atoms, such as polyoxyethylene alkyl ether,
polyoxyethylene polyoxypropylene alkyl ether and polyoxyethylene
alkyl phenyl ether,
(B) partial ester types of polyhydric alcohols and fatty acids
having 12 to 22 carbon atoms, such as sorbitan.fatty acid esters,
glycerin.fatty acids esters, polyglycerin.fatty acid esters,
ethylene glycol.fatty acid esters, polyethylene glycol.fatty acid
esters, propylene glycol.fatty acid esters and
pentaerythritol.fatty acid esters,
(C) ether ester types wherein the number of addition moles of
ethylene oxide is 1 to 30, and a fatty acid has 12 to 22 carbon
atoms, such as polyoxyethylene sorbitan.fatty acid esters,
polyoxyethylene sorbitol.fatty acid esters, polyoxyethylene
mannitan.fatty acid esters, polyoxyethylene glyceryl fatty acid
esters, and polyoxyethylene propylene glycol.mono-fatty acid
esters, and
(D) ester types of ethylene oxide obtained by addition
polymerization, wherein the number of addition moles of ethylene
oxide is 1 to 30, such as polyoxethylene castor oil.hardened castor
oil, polyoxyethylene lanolin derivatives, polyoxyethylene
phitosterol and polyolxyethylene beeswax derivatives.
The nonionic surface active agents having a hydrophilic group
combined with a fluorocarbon group wherein the hydrogen atoms in
the alkyl group, viz., a lipophilic group are substituted with
fluorine are represented by the following general formulae.
wherein
Rf is a fluorinated aliphatic or aromatic group having 1 to 20
carbon atoms provided that the aliphatic group may be straight,
branched or cyclic,
B is a divalent connecting group (e.g., --SO.sub.2 -- and
--CO),
R' is a hydrogen atom or an alkyl group having 1 to 20 carbon
atoms, and
l, m and n each are an integer of 1 to 50.
The more the amount of the hydrophilic nature-affording agent used
with the silicone component in the present invention, such as
hydrophilic silicone oils and nonionic surfactants, the more
remarkable the hydrophilic effect. However, that agent used in an
amount exceeding 5.0 weight %, on the one hand, retards the setting
reaction of the silicone impression materials, and inhibits the
solidification reaction of gypsum and thereby roughens the surface
of gypsum models. When that agent is used in an amount of below
0.05 weight %, on the other hand, no sufficient hydrophilic
nature-affording effect is obtained. Thus, the amount of the
hydrophilic nature-affording agent is suitably in the range of 0.05
to 5.0 weight %. It is understood that these hydrophilic
nature-affording agents may be used alone or in combination with
respect to the silicone impression materials.
In most cases, the silicone impression materials generally comprise
either two-component systems consisting of base and catalyst
components or three-component systems consisting of base, catalyst
and reactor components. The present invention is applicable to any
one of the combinations of the proteins soluble or slightly soluble
in water with the hydrophilic nature-affording agents, as long as
the silicone impression materials contain the required amounts of
at least one of said proteins and at least one of said agents
selected from hydrophilic silicone oils and nonionic surface active
agents.
The silicone impression material used in the present invention may
be any one of the room temperature vulcanizing silicone materials
of the condensation or addition type, and may typically comprise
the following components:
A. Condensation Type Silicone Impression Materials
(a) Hydroxydimethyl polysiloxanes having hydroxide groups at its
both terminals.
(b) Crosslinkers, typically, ortho- or poly-ethyl silicates having
an ethoxy group
(c) Condensation vulcanization catalysts, typically, organometallic
compounds such as dibutyltin acetate, dibutyltin laurate and lead
octenoic acid.
(d) Fillers, typically, diatomaceous earth, calcium carbonate,
silicic acid, calcium sulfate, zirconium silicate, zirconium oxide,
titanium oxide and zinc oxide. Alternatively, fillers
surface-treated with resins, silane or the like.
(e) If necessary, coloring matters, perfumes, fluidity regulators,
plasticizers and the like.
B. Addition Type Silicone Impression Materials
(1) Vinylpolymethyl siloxanes having a vinyl-terminated group.
(2) Hydrogen polymethyl siloxanes having an active
hydrogen-terminated group.
(3) Addition vulcanization catalysts, typically, platinum base
catalysts.
(4) Fillers, typically, diatomaceous earth, calcium carbonate
silicic acid, calcium sulfate, zirconium silicate, zirconium oxide,
titanium oxide and zinc oxide. Alternatively, fillers
surface-treated with resins, silane or the like.
(5) If necessary, coloring matters, perfumes, fluidity regulators,
plasticizers and the like.
EXAMPLES
The present invention will now be explained with reference to the
following non-restrictive examples.
EXAMPLE 1
Condensation Type Silicone Impression Material
______________________________________ (i) Hydroxydimethyl
polysiloxane 70 weight % Silicic anhydride 25 weight % Titanium
oxide 5 weight % 100 weight %
______________________________________
The ingredients (i) were charged with 6.5 weight % of albumin in a
kneader, where they were sufficiently mixed and kneaded together
for 1 hour into a base component.
______________________________________ (ii) Dibutyltin laurate 4
weight % Vaseline 70 weight % Polyethyl silicate 25 weight % Red
oxide 1 weight % 100 weight %
______________________________________
The ingredients (ii) were charged in a kneader, where they were
sufficiently mixed and kneaded together for 1 hour into a catalyst
component.
Equal amounts of the base component and the catalyst component were
mixed and kneaded together for 30 seconds on a mixing pad with the
use of a spatula.
EXAMPLE 2
Condensation Type Silicone Impression Material
The ingredients (i) of Example 1 were charged with 3.0 weight % of
protamine and 3.5 weight % of polyether-modified silicone oil
(manufactured by Shinetsu Kagaku K.K., and available under the
trade name of KF 352) in a kneader, where they were sufficiently
mixed and kneaded together for 1 hour into a base component.
Equal amounts of the base component and the catalyst component
prepared in Example 1 were kneaded and mixed together on a mixing
pad for 30 seconds with the use of a spatula.
EXAMPLE 3
Condensation Type Silicone Impression Material
The ingredients (i) of Example 1 were charged with 4.2 weight % of
albumin tannate, 3.0 weight % of sorbitan.caprilic acid ester and
1.5 weight % of alcohol-modified silicone oil (manufactured by
Shinetsu Kagaku K.K., and available under the trade name of KF 851)
in a kneader, where they were sufficiently mixed and kneaded
together for 1 hour into a base component.
Equal amounts of the base component and the catalyst component
prepared in Example 1 were kneaded and mixed together on a mixing
pad for 30 seconds with the use of a spatula.
EXAMPLE 4
Condensation Type Silicone Impression Material
The ingredients (i) of Example 1 were charged with 0.5 weight % of
albumin and 4.8 weight % of ethylene glycol.caprilic acid ester in
a kneader, where they were sufficiently mixed and kneaded together
for 1 hour into a base component.
Equal amounts of the base component and the catalyst component
prepared in Example 1 were kneaded and mixed together on a mixing
pad for 30 seconds and with the use of a spatula.
EXAMPLE 5
Condensation Type Silicone Impression Material
______________________________________ (i) Hydroxydimethyl
polysiloxane 75 weight % Diatomaceous earth 25 weight % 100 weight
% ______________________________________
The ingredients (i) were charged with 4.4 weight % of gelatin
tannate in a kneader, where they were sufficiently mixed and
kneaded together for 1 hour into a base component.
______________________________________ (ii) Dibutyltin laurate 30
weight % Vaseline 45 weight % Paraffin wax 25 weight % 100 weight %
______________________________________
The ingredients (ii) were charged in a kneader, and were mixed and
kneaded together for 30 minutes, while heated to 70.degree. C.,
thereby preparing a catalyst component.
______________________________________ (iii) Silicone oil 70 weight
% Ethyl silicate 30 weight % 100 weight %
______________________________________
The ingredients (iii) were charged with 1.5 weight % of
sorbitan.monocaprilic acid ester in a mixer, where they were
sufficiently mixed together for 20 minutes into a reactor
component.
Ten (10) parts by weight of the base component were kneaded and
mixed with 2 parts by weight of the catalyst component and 1 part
by weight of the reactor component on a mixing pad for 45 seconds
with the use of a spatula.
EXAMPLE 6
Addition Type Silicone Impression Material
______________________________________ (i) Vinyl polymethylsiloxane
50 weight % (250Ps, 25.degree. C.) Hydrogen polymethylsiloxane 30
weight % (320Ps, 25.degree. C.) Finely divided quartz 20 weight %
100 weight % ______________________________________
The ingredients (i) were charged with 6.5 weight % of peptone and
2.0 weight % of casein in a kneader, where they were sufficiently
mixed and kneaded together for 1 hour into a base component.
______________________________________ (ii) Vinyl
polymethylsiloxane 89.95 weight % (250Ps, 25.degree. C.) Zirconium
silicate 10.0 weight % Choroplatinate 0.05 weight % 100 weight %
______________________________________
The ingredients (ii) were charged into a kneader, and were
sufficiently mixed and kneaded together for 1 hour into a catalyst
component.
Equal amounts of the base and catalyst components were kneaded and
mixed together on a mixing pad for 30 minutes with the use of a
spatula.
EXAMPLE 7
Addition Type Silicone Impression Material
Together with the ingredients (ii) of Example 6 to which 3.5 weight
% of finely divided gelatin and 2.7 weight % of the nonionic
surface active agent expressed in terms of the general formula:
Rf(CH.sub.2).sub.l O(C.sub.n H.sub.2n O).sub.m (manufactured by
Asahi Garasu K.K., and available under the trade name of Surfaron
S-145) were charged in a kneader, where they were sufficiently
mixed and kneaded together for 1 hour into a catalyst
component.
Equal amounts of the base component prepared in Example 6 and
catalyst component were kneaded and mixed together on a mixing pad
for 30 seconds with the use of a spatula.
EXAMPLE 8
Addition Type Silicone Impression Material
Together with 1.5 weight % of gelatin tannate and 3.0 weight % of
polyether-modified silicone oil (manufactured by Shinetsu Kagaku
K.K., and available under the trade name of KF 351), the
ingredients (i) of Example 6 were charged in a kneader, and were
sufficiently mixed and kneaded together for 1 hour into a base
component.
Together with 3.5 weight % of gelatin and 2.0 weight % of
polyoxyethylene nonyl phenyl ether, the ingredients (ii) of Example
6 were charged in a kneader, and were sufficiently mixed and
kneaded together for 1 hour into a catalyst component.
Equal amounts of the base and catalyst components were kneaded and
mixed on a mixing pad for 30 seconds with the use of a spatula.
EXAMPLE 9
Addition Type Silicone Impression Material
Together with 6.5 weight % of peptone and 0.2 weight % of
polyoxyethylene sorbitan.monoisostearic acid ester, the ingredients
(i) of Example 6 were charged in a kneader, and were sufficiently
mixed and kneaded together for 1 hour into a base component.
As the catalyst component, use was made of the catalyst component
prepared in Example 6, which was kneaded and mixed with the base
component in equal amounts on a mixing pad for 30 seconds with the
use of a spatula.
EXAMPLE 10
Addition Type Silicone Impression Material
Together with 2.5 weight % of albumin tannate and 8.2 weigth % of
polyether-modified silicone oil (manufactured by Shinetsu Kagaku
K.K., and available under the trade name of KF 352), the
ingredients (i) of Example 6 were charged in a kneader, and were
sufficiently mixed and kneaded together for 1 hour into a base
component.
Together with 2.0 weight % of casein and 1.0 weight % of
polyoxyethylene propylene glycol-mono-fatty acid ester, the
ingredients (ii) of Example 6 were charged in a kneader, and were
sufficiently mixed and kneaded together for 1 hour into a catalyst
component.
Equal amounts of the base and catalyst components were kneaded and
mixing on a mixing pad for 30 seconds with the use of a
spatula.
EXAMPLE 11
Addition Type Silicone Impression Material
Together with 10.5 weight % of albumin, the ingredients (i) of
Example 6 were charged in a kneader, and were sufficiently mixed
and kneaded together for 1 hour into a base component.
Together with 7.0 weight % of casein and 0.4 weight of
pentaerythritol.fatty acid ester, the ingredients (ii) of Example 6
were charged in a kneader, and were sufficiently mixed and kneaded
together for 1 hour into a catalyst component.
Equal amounts of the base and catalyst components were kneaded and
mixed on a mixing pad for 30 seconds with the use of a spatula.
COMPARATIVE EXAMPLE 1
Condensation Type Silicone Impression Material
The ingredients (i) of Example 1 were charged in a kneader, and
were sufficiently mixed and kneaded together for 1 hour into a base
component.
Equal amounts of the base component and the catalyst component
prepared in Example 1 were kneaded and mixed together on a mixing
pad for 30 seconds with the use of a spatula.
COMPARATIVE EXAMPLE 2
Addition Type Silicone Impression Material
The ingredients (i) of Example 6 were charged in a kneader, and
were sufficiently mixed and kneaded together for 1 hour into a base
component.
Equal amounts of the base component and the catalyst component
prepared in Example 6 were kneaded and mixed together on a mixing
pad for 30 seconds with the use of a spatula.
COMPARISON EXAMPLE 3
Addition Type Silicone Impression Material
Together with 15.0 weight % of polyoxyethylene sorbitan.monostearic
acid ester, the ingredients (i) of Example 6 were charged in a
kneader, and were sufficiently mixed and kneaded together for 1
hour into a base component.
Equal amounts of the base component and the catalyst component
prepared in Example 6 were kneaded and mixed together on a mixing
pad for 30 seconds with the use of a spatula.
With the products of Examples 1 to 11 and Comparative Examples 1 to
3, testings were undertaken for setting time, wettability of the
impression materials with respect to saliva, clearness of the
details of impressions, wettability of the registered surface of
the impressions taken with respect to gypsum slurry and surface
roughness of gypsum models. The testing results are summarized in
Tables 1 and 2.
TABLE 1
__________________________________________________________________________
Condensation Type Silicone Impression Material Wettability of
impression Clearness of Wettability of material with respect to
impression impression Saliva (angle of contact details (width
surface with Surface Setting of advance of artificial of fine lines
respect to roughness of Time saliva) reproduced) gypsum slurry
gypsum model
__________________________________________________________________________
Example 1 4 min 30 sec 45.degree. 20 .mu.m Satisfactory 2.8 .mu.m
Example 2 4 min 30 sec 42.degree. 10 .mu.m Very 3.3 .mu.m
Satisfactory Example 3 4 min 30 sec 40.degree. 10 .mu.m Very 3.6
.mu.m Satisfactory Example 4 4 min 30 sec 47.degree. 20 .mu.m Very
3.0 .mu.m Satisfactory Example 5 5 min 00 sec 40.degree. 10 .mu.m
Very 3.2 .mu.m Satisfactory Comparison 4 min 30 sec 80.degree. 50
.mu.m Unsatisfactory 3.6 .mu.m Example 1
__________________________________________________________________________
TABLE 2
__________________________________________________________________________
Addition Type Silicone Impression Material Wettability of
impression Clearness of Wettability of material with respect to
impression impression saliva (angle of contact details (width
surface with Surface Setting of advance of artificial of fine lines
respect to roughness of Time saliva) reproduced) gypsum slurry
gypsum model
__________________________________________________________________________
Example 6 4 min 20 sec 58.degree. 20 .mu.m Satisfactory 2.4 .mu.m
Example 7 4 min 30 sec 40.degree. 10 .mu.m Very 2.5 .mu.m
Satisfactory Example 8 4 min 30 sec 48.degree. 10 .mu.m Very 2.7
.mu.m Satisfactory Example 9 4 min 30 sec 43.degree. 10 .mu.m Very
2.7 .mu.m Satisfactory Example 10 4 min 40 sec 58.degree. 20 .mu.m
Very 3.5 .mu.m Satisfactory Example 11 4 min 40 sec 42.degree. 20
.mu.m Very 3.0 .mu.m Satisfactory Comparison 4 min 30 sec
85.degree. 75 .mu.m Unsatisfactory 2.7 .mu.m Example 2 Comparison 8
min 30 sec 45.degree. 10 .mu.m Unsatisfactory 8.5 .mu.m Example 3
__________________________________________________________________________
For the measurement of setting time, a sample was placed in a
stainless steel ring of 8.0 mm in height, 24.0 mm in inner diameter
and 1.0 mm in thickness in a constant temperature chamber
maintained at a temperature of 23.+-.2.degree. C. and a humidity of
50.+-.10%. An 150 g loaded Vicat needle (of 3.0 mm in diameter) was
stuck down into the sample. The setting time was found by measuring
a time span from the time of start of mixing to the time at which
the needle was stuck down into the sample by only 1.0 mm or
lower.
For measuring the wettability of the impression materials with
respect to saliva (expressed in terms of the angle of contact of
advance of artificial saliva), the artificial saliva of Green Wood
was added dropwise onto the plane of a cured sample impression,
which was then inclined at an angle of 6.degree. to measure the
angle of contact of advance of the artificial saliva.
For measuring the clearness of the details of a sample impression
(expressed in terms of the width of fine lines reproduced), a model
under test having four types of fine lines, each of 25 mm in length
and 10 .mu.m, 20 .mu.m, 50 .mu.m or 75 .mu.m in width, was immersed
in artificial saliva for wetting according to ISO 1563. Thereafter,
a sample impression material was filled and pressed in that model,
immersed in water of 35.degree. C. for 4 minutes, and was removed
to take the impressions of the fine lines. The surface of the thus
obtained impressions was observed under a 6 to 10-x magnifying
glass, while it was illuminated at a low angle. The clearness was
indicated by the width of the finest one of the lines reproduced
continuously over the full length.
For measuring the wettability of the impression surface with
respect to gypsum slurry, dental super-hard gypsum (manufactured by
GC Dental Industrial Co., and available under the trade name of
Fujirock) was mixed with water in a P:W ratio of 100:20 (by
weight), and the resulting mixture was cast onto the impression
obtained in the clearness testing to visually observe and estimate
the wettability of the gypsum slurry with respect to the
impression.
For the surface roughness of a sample gypsum model, the impression
of the smooth surface of a glass plate was first taken. The dental
super-hard gypsum was mixed with water in a P:W ratio of 100:20 (by
weight), and the resulting mixture was cast onto that impression.
The gypsum was set after the lapse of 30 minutes or longer.
Thereafter, the set gypsum was released from the impression, and
was measured on the surface with a surface roughness meter
(manufactured by Tokyo Seimitsu K.K., and available under the trade
name of Surfcomb 30B) according to JIS-B0601 to obtain ten
measurements which were then averaged.
As can be understood from the results of the condensation (Table 1)
and addition (Table 2) type silicone impression materials, the
present silicone impression materials to which the proteins soluble
or slightly soluble in water were added (Examples 1 and 6) and the
present silicone impression materials to which added were the
combinations of the proteins soluble or slightly soluble in water
with the hydrophilic nature-affording agents such as hydrophilic
silicone oils and nonionic surfactants (Examples 2-5 and 7-11) show
more satisfactory wettability with respect to saliva at the time of
taking the impression of the oral cavity, as compared with the
conventional silicone impression materials (Comparative Examples 1
and 2). Thus, since the present materials have no repelling action
on saliva, they make it possible to take clear impressions of the
details of the oral cavity, even when it is wetted with saliva. In
addition, since the registered surface of the impression taken at
the time of preparing a gypsum model shows satisfactory wettability
with respect to gypsum slurry, and has no repelling action
thereupon, it is possible to allow the gypsum slurry to be cast
into the details of the impression surface without any entrainment
of air bubbles and, hence, obtain a precise gypsum model. Further,
since the amount of the hydrophilic nature-affording agents such as
hydrophilic silicone oils and nonionic surfactants to be used is
reduced and limited, the setting reaction of silicone rubber such
as condensation or addition vulcanization is not inhibited at all.
Nor is the setting reaction of gypsum inhibited. Thus, there is
neither delay in the setting time nor surface roughening of gypsum
models, unlike the silicone impression material (Comparative
Example 3) containing a larger amount of the nonionic surface
active agent.
* * * * *